One Deadly Punch
by Tectonix
Summary: The Sins are on a vacation from hero stuff, but along comes an assignment from the King to explore and investigate a newly discovered continent. But it has a catch- the second reason for sending the Sins lies with the vision of the Ten Commandments, a second vision which portrays a golden armor- clad entity possessing immense power. Will the Sins be able to stop this alien threat?
1. Chapter 1

**Finally, I yielded to the unending urge to make a fanfic about the Seven Deadly Sins and One Punch Man. Don't blame me for quality issues this is the first fanfic I made and I'm on mobile. Inspiration came from Warmachine375 and his fanfic Fairies and Sins. It's a really cool fanfic so please check it out. And now without further ado, let's get to it!**

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 **Chapter 1: The Arrival**

On the outskirts of the One Punch Continent, (there's literally no info about its name so I just made that up) eight people and 1 pig are travelling on what seems to be a witch hat-shaped cottage. This cottage is on top of what seems to be a giant green boar, for some reason. In reality, this cottage is the Boar Hat, a fine drinking establishment with a reputation of horrible food (before Ban came along) but good liquor, which is run by the one and only Meliodas, midget leader of the Seven Deadly Sins. (I'm going to skip introductions since you all know who and what the Seven Deadly Sins + Elizabeth and Hawk look anyway)

"Are we there yet?" says Ban due to extreme boredom. "I'm not sure. Merlin, can you locate where we are?" the midget leader asked in response of the immortal's question. "Captain, it seems we are nearing a settlement. We might be approaching our destination." says the wizard with the very revealing outfit. "Remind me why we're here again?" a kid on a floating pillow asked. "King Baltra told us of a newly discovered continent and of a new vision about a certain golden-armored entity with immense power. We're here to explore and investigate. Just think of this as a vacation. Plus you could spend time with Diane, right King?" the midget captain explained. King stuttered and blushed at this, and attempted to retort, but all that came out was a babbling mess.

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When they finally neared the nearby settlement, they all had different reactions, mostly shocked. One of them was Elizabeth's, but not due to curiosity but merely due to the fact that the place was _smoking_. "Umm… Sir Meliodas? Is the settlement okay?" the naïve princess questioned. "I don't know, but I'm going ahead to scout if there's any trouble. You guys should catch up soon." As he jumps of Hawk Mama and starts making his way to the battered city.

When he finally reached the city, he sensed a powerful presence and followed it. The trail led him to a broken battlefield, with a piccolo reject standing in the center. The piccolo reject suddenly conjures up a few glowing balls of energy and swiftly launches them towards a few buildings, effectively increasing One Punch Man's property damage counter. As the piccolo reject laughs maniacally, it takes notice of a crying little girl and tries to grab her, but to no avail. Meliodas caught the girl in the nick of time before she was destroyed by the grip force of the steroid-rich piccolo rip-off. "Oh? A little boy is going to battle me? And who might you be?" the copyright monster boomed. "The name's Meliodas, and I'm not a kid. I'm a Holy Knight." The captain of the Sins said seemingly innocently. "A 'Holy Knight' you say? A mere child with a ridiculous imagination is going to fight me? What a half-assed backstory! I was created by Mother Nature in order to fight back against the human race, born from their pollution! I am Vaccine Man! And you're going to fight me because of your make-believe stories?!" the copiccolo bellowed as it began a hideous transformation, with its spikes and teeth tripling in size and sharpness. The monster also grew to extreme levels, as it tried to annihilate Meliodas only for him to dodge with ease. Vaccine Man frantically attacked Meliodas at any chance he can, but could not even land a single blow. As Vaccine Man attacked and missed he got slashed by an unknown object. And then he was slashed again. And again. And again. And again. Every single time it missed it seemed he would get hacked at by an unknown object. As the piccolo reject stumbled down in pain, Meliodas landed on the ground, unscathed by Vaccine Man's attacks and revealing a curved shortsword with a dragon engraved in its hilt, however the monster itself was a different story. Slash wounds here and there, Vaccine Man had taken a lot of damage, unable to keep up with the stronger opponent. "Gah! Perhaps it's not make-believe. For now, at least." Bellowed the hurt monster. As the monster recovered, it unleashed a large ball of pure energy to strike its enemy down. As the mass if energy approached Meliodas, he shouted two words:

"Full Counter!"

Full Counter seemingly reflected the attack back to Vaccine Man, albeit double the power. Unable to defend itself as it was still in a state of shock, it was hit point-blank with a powerful energy ball. Narrowly escaping with a lot more injuries, Vaccine Man put some distance between itself and the midget captain. "So you can reflect attacks huh? Well let's see how you like this!" the piccolo reject boomed as it launches a volley of 5 energy balls at the same time. "Try reflecting that, asshole!" but it was in for a surprise. Meliodas seemingly _splits_ into five and simultaneously uses Full Counter to reflect the attacks with double the power. 3 out of 5 balls hit Vaccine Man, but still enough to gravely injure it. As soon as Vaccine Man lands on the ground, it starts to recover and summons dozens of energy beams to attack Meliodas, while the latter began to dodge the beams swiftly while Vaccine Man launches even more beams. "DIE! DIE! DIE! DIE! DIE!" the piccolo reject screams in quick succession. After the intense bombardment, Vaccine Man scanned the surroundings to find his enemy, hopefully dead. His hopes are realized as he founds the body of Meliodas tattered and full of holes. "Perhaps I was wrong for even believing his stupid imagination." boomed the copiccolo. At that exact same moment, the rest of the Sins arrive and are shocked for a brief moment (except Elizabeth, because she was shocked for a long time) and ran to confront their enemy. Unbenknownst to Vaccine Man, the dead body of Meliodas quickly fades and reveals that it was a clone and that the true Meliodas was hiding behind the piccolo reject all along, and at the exact right moment, he shouted:

"Divine Slayer!"

After what seems to be a split second, Vaccine Man was sliced multiple times as if a master swordsman was his enemy. "Maybe you're the one without imagination. I told you Holy Knights are real." retorted the midget captain towards its earlier remark. However, it miraculously survives and begins charging its power. "IF I YOU'RE GOING TO KILL ME, MIGHT AS WELL BRING THE WHOLE CITY ALONG WITH ME!" boomed the deranged piccolo reject. "This is bad. Even Captain will have some difficulty repelling that attack." The revealing magician comments, watching from the sidelines, as Meliodas readies for the attack. Oddly, the attack never came. In the place of Vaccine Man was a huge fountain of blood and behind it was a bald man in a yellow suit with an outstretched _smoking_ fist. The bald man then suddenly cried out, "DAMNIT ALL IT TOOK WAS ONE PUNCH AGAIN!" as he groveled on the ground. It wasn't until the baldy stopped wallowing when he finally noticed the awestruck expressions on their faces.

"So… who are you guys?"

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 **Author's Note: There you have it folks! The very first chapter of the very first fanfic of the Seven Deadly Sins and One Punch Man. This is obviously an AU story. Please don't hate me because I am very tired since I wrote this at about 5 AM and I lost inspiraton halfway through. So yeah this fanfic will be set at the post-Kingdom Infiltration Arc but the Sins are on an assignment from the King and that they have their sacred treasures and Escanor tagged along. What would happen if Saitama fought The One? Stay tuned to find out and peace!**


	2. Chapter 2

**Desire to write has won again. Please don't hate me if the story is bad because I haven't got much inspiration to do and DANG is writing a fanfiction hard. And with that, I have run out of things to say and please enjoy the chapter.**

 **Disclaimer: I do not own the Seven Deadly Sins and One Punch Man. They belong to the respective owners. If I did, One Punch Man would have a season 2 this year.**

 **Chapter 2: Settling**

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"…so who are you guys?"

The Sins immediately assumed battle stances, preparing for any sudden movement. They had been new to this land, so better be safe than sorry as they had little information to work with. As they stood defensively, the bald man merely tilted his head slightly in confusion, his emotionless plain face still dominating his entire image. He was pretty sure he didn't do anything wrong, so why were they defending themselves? Maybe they're overreacting? Paranoid? The baldy didn't really care as all he wanted to do right now was to go to the supermarket, as there was a huge 75% off sale that was rudely interrupted by the appearance of a mysterious being.

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As the Sins masterfully observe even the most subtle of the baldy's movements, they could sense no hostility whatsoever. He was just standing there, rubbing his face with the ultimate poker face. At the same time all of them had thoughts flashing through their minds, such as how this man obliterated a monster with one punch, how'd he get so strong, and how many leftovers would be on his bowl tonight (Hawk is hungry).

After a while of silence and even more silence, with the occasional loud rumble of ambulances and government vehicles sent to help the injured, the tension had finally eased up. The Sins lowered their guard seeing that this man was not an enemy. The bald guy still hasn't changed his face. After the long silence, Meliodas finally spoke up, "Who are you? And how did you kill the monster in one punch?". Seeing that he can finally talk, the baldy replied, "I'm Saitama, the hero for fun. How about you guys?" the Sins replied by stating their name and title, one by one, with Meliodas going last and stating himself as the captain of the Seven Deadly Sins (its too long to write so have fun with imagination). After the Sins lengthy introduction, the baldy—I mean Saitama merely voiced out an emotionless "Ok" at them and took off, saying that he had to go to a 'supermarket sale' while leaving the Sins confused at the term.

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A few hours after their encounter, the Sins have reached City A unknowingly, and after finding an empty lot, settled the Boar Hat onto ground level, still on Mama Hawk's back. "Huh, this place seems so different from back home in Brittania. In order to cover as much as ground as possible, we should split up. We need to learn more about this place. Merlin will be with Gowther, Diane will be with King, Ban will be with Escanor, and Elizabeth will come with me. Hawk will stay in the Boar Hat since as far as I know, the people here don't have random talking pigs walking around. Diane, you should shrink down too. Escanor and Ban will stay in the Boar Hat to entertain any customers." The Sins reply to this with an eager shout of 'roger'.

After a few hours of exploring with Elizabeth, who got a few perverted gazes on her due to her skimpy outfit, Meliodas finally decided to return to the Boar Hat to report their findings. When they got there, they were the 2nd group to return, as King and Diane had returned before them due to an incident with King having a nosebleed. After a short while, Merlin and Gowther returned to the Boar Hat. "It seems that this continent is more technologically advanced than Brittania, being able to make a number of automated transportation devices, the most common of which being the 'automobile' or the car. They also have created numerous devices that store information, with a small handheld device capable of storing libraries of books with relative ease. They have also created an advanced system of communication and information sharing called the 'Internet' that stores countless information and most of their devices are linked to it. They are also unaware of the presence of magic and the other four clans, with only humans populating the entire continent along with animals. There are also these 'mysterious beings' that plague their society with an association of heroes to combat them." Inquired Merlin with a smirk. "Me and King went to one of the buildings called a 'mall' and found many things for sale there! It's basically a giant marketplace! I went to the 'department store' and I found a ton of clothes on display for sale! I tried one on, but we couldn't pay for it because we don't have money and King had a nosebleed." Replied Diane with a gleeful tone. Meliodas replied with a smirk greater than Merlin's own "I discovered better underwear for Elizabeth."

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After a long while, night had finally appeared and the Boar Hat was surging with customers. Apparently the first few customers were enthralled by their liquor and spread the news. Now the Sins were hard at work with Ban cooking furiously, Elizabeth, Gowther, Diane, and Escanor serving and taking orders from a wave of demanding customers, Meliodas helping out Ban cook (oh god) but thankfully was only cutting the ingredients, while King and Merlin were buying tons of ingredients from a grocery store. Even though they were unfamiliar with the new names for food and items, they managed to buy the right ingredients with an add on of junk food from King.

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After a few days after settling in A City, the Sins had been well versed in the cities and buildings in the continent. They also apparently learned that they needed a permit to sell food at the Boar Hat, so Merlin decided to do some paperwork. It was a small day off for the Sins after a non-stop surge of customers per day and they finally had time to rest while Merlin legalizes them. They had been exploring again today, but unlike last time, they were staying as a group rather than splitting up. They had _conveniently_ wandered off into Z City after hearing rumors about mysterious beings lurking about in the ghost town. It was only then after appearing after several minutes a warning was shot from the speakers saying all citizens are advised to stay indoors due to a massive case of pesky mosquitoes literally sucking animals and humans dry.

Meanwhile, another One Punch Man character lurks in the forest seemingly hunting down the cause of the mosquito frenzy.

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 **Author's Note: You all know who this character is. I just went for this chapter t** **o focus not so much on the story but on the experiences of the Sins in accepting modern society. I know, its dissappointing. Next chapter will probably be about Episode 2 of One Punch Man, the Mosquito Gurl fight, and the House of Evolution stuff. Stay tuned to continue reading, I guess.**

 **After the first story it felt like all the creative juices were sucked dry by a horde of hungry mosquitoes. I can't even think of a good storyline until after a few weeks. If anyone is willing, I would like to ask for an editor to proofread my story. Besides my perfectionist instincts had been forcing me to disregard the drafts and start over. I wrote this at midnight and I'm way past my already messed up sleep schedule so I'm tired and drowsy and good night people. Or morning. Or afternoon. Or evening. I don't know, whatever time it is. (ITS ADVENTURE TIME!) *sobs***


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